1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to an optical transmission line monitoring device used in a monitoring device on an optical transmission line, an optical transmission line monitoring method, and a computer program.
2. Description of Related Art
Conventionally, a communication device installed at a communication station and a plurality of terminating devices installed in users' homes are connected by optical fiber cables (hereinafter ‘optical fibers’) in a star-type interconnection or the like to construct an optical transmission line.
To monitor such an optical transmission line after it is constructed, for example, an optical pulse is introduced along the longitudinal direction of the optical fiber of the transmission line using optical time domain reflectometers (OTDRs), and a measurement is token of returning light based on reflection from devices and Rayleigh scattering generated by the incidence. The measurement is contrasted with device information created at the time of design based on construction design plans, and stored as initial measurement data. Device data includes data relating to terminating devices constituting a device on the optical transmission line, optical fiber fusion points, types of connection devices such as connectors for connecting the optical fibers, and information relating to positions and names of these pieces of the device.
By storing the device data and the initial measurement data as described above, measurement data of the next monitoring process can be contrasted with the initial measurement data, and, when a failure is detected, the location and status of the failure can be identified by referring to device data arranged in correlation with the initial measurement data (e.g. see Japanese Patent No. 2674659).
However, to pre-register device data and initial measurement data is problematic in that taking one measurement using OTDR or the like and correlating this measurement with the device data requires a long time, and is burdensome in regard to cost.
Furthermore, on an optical transmission line whose line status is frequently changed, the device data and the initial measurement data must be changed every time, resulting in a problem that a next monitoring process cannot be performed until these changes are completed.